1. Field of the Invention
This invention relates to a processing machine in food industry, specifically, a new sterilizing device for liquid beverage or liquids.
2. Description of the Related Art
High intensity pulsed electric field (PEF) technology is used for enzyme-inactivating and sterilizing in food industry based on cellular structure and differences in electric properties within liquid food systems. When liquid food is placed in electric field as an electric medium, the cell membrane of microorganism in food is electrically broken down by strong electric field action, thus causing irreversible membrane electroporation or disruption, damaged cell tissues, and consequently microbial inactivation. It has been proved that food can be sterilized effectively under conditions of pulsed electric field at 12-40 Kv/cm (kilo volts per centimeter) and pulse duration of 20 μs-18 μs (micro-seconds), with square wave pulse waveform being the most effective. Scientists have made a lot of researches on PEF sterilization and applied for many patents, such as CN2004201123797, CN011300647, CN2009100954911, CN2009100954907 and CN2009100213384.
However, all technical solutions of the aforementioned patents impose high pulsed electric voltage in liquid to form high intensity pulsed electric field, so that bacteria contained in liquid are electroporated and consequently inactivated when exposed to a high intensity pulsed electric field. This kind of technical solution requires high intensity pulsed electric voltage firstly, so inevitably brings about high energy consumption, high technical requirements for equipment and definitely with some risk factors. Most of all, the pulsed electric field theory fails to ensure a same PEF intensity for liquids of diverse physical and chemical parameters which may present at any time for beverage product line, thus causing instability of sterilizing effect.
Under the same electric voltage, changes of physical parameters of the liquid, such as electric conductivity and dielectric constant, would substantially affect electric field intensity in the liquid, thus affecting sterilizing effect. To date, most of PEF sterilizing researches fail to address this important issue, which prevents the application of PEF sterilizing technology in actual beverage lines.